The present invention relates to a box for cultivating plants which can readily make a natural garden on the roof of veranda of a building.
Owing to the remarkable progress of urbanization, most of the buildings in the cities and towns are made of concrete with flat concrete roofs.
The roofs of such buildings have grey rough surfaces thereof exposed so that a bird's-eye view of the city is almost uniformly grey. Furthermore, such roofs have not been used for any useful purposes.
Although some buildings utilize the roofs thereof for small play or leisure areas, such roofs still have the following problems.
Namely, in summer, the temperature of the surface of the roof rises up to 50.degree. to 70.degree. C. at noon due to the heat energy from the sun and the roof can hardly be used as a play or leisure area.
Furthermore, besides the roof of the building, the rooms located right below the roof become hot due to the radiation or conduction of the heat energy of the sun through the roof so that the air conditioning for cooling the rooms cannot cool the rooms sufficiently and the users of the rooms suffer a discomfort.
On the contrary, in winter, since such roof made exclusively of concrete has a poor insulation value, the heat energy of the rooms right below the roof escapes rapidly through the roof so that the heating system cannot warm the room sufficiently, resulting in an increase of cost for heating.
For resolving above defects of such roofs, people have tried to make the roof full of natural greenery. Such scheme has not been realized, however, since several problems such as the increase of the weight of the roof, water drainage, the weight of people standing on the roof or the possibility of plant cultivation on the concrete roof have not been resolved.
Accordingly, the installation of artificial turfs on the roof has been realized for providing greenery on the roof.
The artificial turfs, however, absorb and preserve the heat energy from the sun, the roof becomes extremely hot and gives discomfort to the people on the roof. Furthermore, the dust gradually accumulates in the turf and such dust cannot be removed easily so that the roof becomes unsanitary and the turf becomes faded.
Furthermore, the temperature of the surface of the concrete roof differs sharply between summer and winter at a level of about 70.degree. C. so that the concrete roof expands and contracts sharply giving rise to cracks on the roof, and such cracks cause roof leakage which brings about damage of household goods such as wardrobes or the disturbing sound of feet of people walking on the roof penetrates the roof and echos in the room right below the roof of the building.
Accordingly, it is an object of the present invention to provide a box for cultivating plants which can overcome the above-mentioned defects of conventional roof structures and can provide natural greenery on the roof.